Hum/Noise Problem with EBS Microbass II

russianspy · #1 02-21-2008, 12:16 PM

Hi all. Longtime member here, but I actually don't remember ever starting a thread. Maybe years ago.

Anyways, I recently bought an EBS Microbass II from a fellow forum member here. I've been using it almost daily since receiving it and I absolutely love it. However, recently I noticed a problem. Generally, I use it with 9v power as a headphone amp for practicing in my living room or recording on my computer. But recently, I tried powering it using a 1-spot DC adapter.

The pedal output so much hum that it's virtually unusable. The stranger thing is the the adapter doesn't even have to be plugged in to create the hum. If I plug the adapter into the wall and have the pedal running off a 9v, I can hear the hum somehow coming through the air. Very strange. So I tried using another 9v adapter my roommate had laying around. It did not create as much hum as the 1-spot, but it was still a significant problem.

So I guess I can assume something is probably wrong with the 1-spot adapter, but is there a problem with my EBS pedal? Is hum normal when using an AC adapter? Or am I just having problem with the power in my apartment?

niftydog · #2 02-21-2008, 03:10 PM

It seems as if you need a power supply with better filtering. If it varies depending on which power supply you use, then it clearly has to be linked to the power supply.

Stick with old-style "linear" (read "heavy"!) power supplies that are of good quality and have a high current rating. The 1 spot is not a linear supply, it's a switch mode supply, and these are, IMHO, not the best choice for audio applications.

russianspy · #3 02-22-2008, 10:26 PM

I'll try to see if I can borrow one from a friend to try it out before buying one. Anyone else? Any Microbass owners experienced any of these symptoms?

i2k · #4 02-23-2008, 07:15 AM

I heard that 1 spot or any other switch mode power supply can cause hum on some pedals even without connection to it.

I have a Microbass, never had any problem with regulated old school power supply.

russianspy · #5 02-23-2008, 12:50 PM

Well, alright then. I'm gonna definitely look into a different adapter this weekend. I'll report back with my findings. Thanks for the help guys.

russianspy · #6 02-23-2008, 02:36 PM

Thanks alot i2k and niftydog. I went to guitar center and picked up a Morley regulated linear power supply. No hum at all now. Just like using batteries.

Swift713 · #7 02-23-2008, 04:24 PM

Wow, this makes some kind of sense. I got a one spot a few months ago to replace a few wall warts and I have noticed that I get a lot of noise through headphones or running at instrument level into my 4track or mixer. I've been using my amp as a DI to sort of ground this noise but it seems a little silly running my amp just for noise suppression. My compulator makes enough noise with the one spot that I use batteries in it.

bassspielplatz · #8 02-29-2008, 12:45 PM

EBS has an adaptor for the EBS, the AD 9. I think it's always better to use the recommended power supply.
On a separate tread, I made a comment about my Microbass causing a loss of gain on my signal chain. I'm gonna get this adaptor to see if it helps.